Identify the number of neutrons in one atom of sulfur with an isotopic mass number of 34 amu.

So, using the periodic table of elements, we know that the atomic number of sulfur is 16, which stands for the number of protons/electrons in the atom. Since the mass number, in this case is 34, is the sum of protons and neutrons, all we have to do is subtract 16 from 34, which will give us 18, the number of neutrons for this isotope of sulfur. :)

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -

26.4 is about the right time